It is well known that in the beverage, pharmaceutical, concrete mixing, and various other industries that precise volumetric quantities of fluid are required. For example, in the beverage industry it is important to mix exact quantities of syrup with carbonated water in order for the beverage to acquire the proper taste. The pharmaceutical industry :requires exact volumes of fluid for prescription drugs, intravenous solutions and other over-the-counter preparations. The need for precise volumes of fluid is also required in the concrete mixing industry. It is well known that along with water, liquid-based strength additives are added to cement and a mineral aggregate to form superior types of concrete.
Currently, predetermined volumes of fluid are provided by devices that operate upon physical characteristics such as pressure or weight. One such device employs Boyle's Law, which states that if a gas or liquid is kept at a constant temperature, the pressure and volume are in inverse proportion or have a constant product. Although this law is useful, it is only approximately true. Boyle's Law is graphically represented by an equilateral hyperbola. Therefore, the volume of liquid contained within a collector or pressure vessel may be logarithmically derived from the pressure therein. As will be appreciated by those skilled in the art, using Boyle's Law to determine a precise volume of fluid has several drawbacks. First, the level of accuracy in measuring the volume is diminished because a logarithmic function is required to measure the volume. Secondly, the pressure transducer must undergo frequent maintenance checks because of its close proximity to the fluid being measured.
Another method for determining a volume of fluid is by employing a weighing system. This method: requires that a tare weight be read before filling a container with fluid. After filling the container with fluid, the weight of the filled container is read and the volume of fluid contained therein is determined. This method of determining the amount of fluid in a container also has several drawbacks. First, the additional use of a weighing scale is required, along with compensation for the tare weight. Furthermore, the accuracy of any reading is diminished because of external forces applied to the container, such as hoses and supports, during the weighing process. It is also known to employ a positive displacement pump to measure the volume of fluid.
Based upon the foregoing, there is a need in the art for a simple yet accurate device for collecting and dispensing a precise volume of fluid. Additionally, there is a need for a fluid collecting and dispensing device that can be used in either wet line or dry line applications. There is also a need for a precise volume fluid collecting and dispensing device that can be retrofitted to existing fluid dispensing systems.